The nature and derivative of logarithm represent power, log(a)(b) represents base a, and logarithm * of b represents multiplication sign,/represents the definition of division sign: if a = b (a > 0 and a≠ 1), then n=log(a)(b) Basic property:1. 3 . log(a)(M/N)= log(a)(M)-log(a)(N)； 4. Journal.